Rotary compressor or pump



Sept. 8, 1936. B. LlGHTMAN I ROTARY COMPRESSOR OR PUMP Filed Sept. 24, 1935 2 Sheets-:Sheec 1 P 1936- B. LIGHTMAN 2,053,724

ROTARY COMPRESSOR OR PUMP Filed Sept. 24, 1935 2 Sheets-Sheet 2 ICIR W E 7 Y/M/ZZZZZAA/ Patented Sept. 8, 1936 UNITED STATES ROTARY COMPRESSOR OR PUMP Bernard Lightman, Johannesburg, Union of South Africa Application September 24, 1935, Serial No. 41,913 In Great Britain October 1, 1934 13 Claims.

This invention has reference to rotary compressors or pumps.

It relates especially to rotary fluid compressors or pumps of the kind including an external rotated element or, casing, an internal rotating element or rotor which is eccentrically disposed within and against the external element or casing and rotates in contact with the inner surface thereof, and forms a crescent-shaped space between its outer surface and the inner surface of the casing, one or more radial vanes which are slidably mounted in the rotor and maintained in contact with the inner surface of the casing in order to sub-divide the said crescent-shaped space into two or more suction and compression, or working, chambers, inlet means for admitting fluid to said working chambers, and outlet means for conducting away the fluid after it has been compressed or subjected to pressure in said chambers due to the rotation of the casing and rotor.

In rotary fluid compressors or pumps of the kind referred to an arrangement has been proposed wherein the external element or casing is rotated by rolling, and the internal element or rotor is caused to rotate about a free axis by rolling on the inner surface of the casing under the action of gravity.

The object of the present invention is to improve and simplify the construction of rotary fluid compressors or pumps of the kind referred to, and to render the same more efficient in operation.

According to this invention the rotary compressor or pump includes a plurality of the external rotated elements or casings and internal rotated elements or rotors eccentrically arranged therein. Each external element or casing is rotatably carried or supported and caused to roll around a surface, and the shaft or trunnions of the internal element or rotor is or are arranged or journalled in bearings which are eccentric to the axis or centre line of the external element or casing, and said shaft is adapted to be adjusted in relation to the axis of the casing in such a way as to allow pressure to be applied to the internal element or rotor to keep it closely in rolling frictional contact with the internal surface of the casing in order to ensure their rotation and at the same time to provide efficient sealing contact between the casing and rotor to prevent leakage of the fluid from the one or compression chamber to the other and suction chamber. It follows that in this construction the axis of the inner element or rotor is fixed relative to the axis of the external element or casing, and that the axes of both of said elements, after any necessary adjustment has been effected, are maintained at a fixed or constant distance apart.

For closing the ends of the crescent-shaped space between the casing and rotor, and for pre- 5 venting leakage of the fluid from the compression chamber to the suction chamber at the ends of the rotor and vane or vanes, a relatively nonrotatable adjustable member or disc is positioned in the casing at each end thereof. The relatively 19 non-rotatable end member or disc is provided with a stufling box and gland, or equivalent device, around the shaft of the rotor.

If the'arrangement includes a single radial vane, then it is arranged in a longitudinal central slot in the rotor, and springs are provided for keeping the outer edge of the vane in tight sliding contact with, or pressed against, the internal surface or wall of the casing. The sliding vane may be built up or constructed of a plurality of separate leaves or longitudinal parallel sections arranged in juxta-position. Separate springs are preferably employed for forcing and maintaining each of the leaves independently in contact with the wall of the casing. This ensures contact along the outer edge of each leaf of the vane with the wall of the casing.

The fluid is conducted into the suction side of the crescent-shaped space at the back of the vane, and the compressed fluid is conducted from said space at the front of the vane.

The compressor or pump may incorporate means for ensuring positive rotation of the internal element or rotor within the external element or casing.

The compressor or pump may be actuated by rolling the external element or casing around or within a cylinder and/or toothed surface.

A plurality of the compressors or pumps are co-operatively combined and caused to roll around a common central axis and in contact with a cylinder and/or toothed surface. The cylinder and/or toothed surface or surfaces may be fixed on a central shaft, and the central shaft be provided with a non-rotatable toothed wheel, and the shafts or trunnions of the rotors with toothed wheels meshing with and rolling round said stationary toothed wheel to ensure positive rotation of the rotors with their respective casings.

In an arrangement including two only of the compressors or pumps operating around a common central shaft, means may be provided for connecting the pumps or compressors together at diametrically opposite points equidistant from the central shaft, and said means incorporate devices for drawing the rotors in the direction of the central stationary shaft in order adjustably to apply the requisite pressure between the rotors and their lines of rolling contact with the internal walls of their respective casings. The driving means may also be conveniently combined with the last-mentioned devices. The fluid may be admitted through the rotor shaft or trunnion and rotor into the suction side of the crescent-shaped space, and the outlet be taken from the other or compression side of said crescentshaped space, through the rotor and its shaft or trunnion at the other side of. the rotor, and through the medium of a swivel connection to and through the central stationary shaft.

The end members or discs positioned inside the casing at the ends of the one pump or compressor may be adjustably connected to the end members or discs of the other pump or compressor at the same side, in order to prevent rotational movement of said members in the ends of their respective casings.

The invention will be described in greater detail with the aid of the accompanying drawings, wherein Fig. 1 is an elevation of an embodiment of the invention, in which two of the pumps or compressors are co-operatively combined.

Fig. 2 is a section of Fig. 1' on line :c:z:.

Fig. 3 is a section of Fig. 1 on line yy Fi 4 is a section of Fig. 1 on line z-z.

Fig. 5 is a sectional view illustrating a detail of the outlet passage from the rotor trunnion.

Fig. 6 is a longitudinal sectional elevation oi one of the compressors or pumps, drawn to an enlarged scale.

- Fig. 7 is a section of Fig. 6 on line a: ar

Fig. 8 is a central sectional plan of the rotor and its trunnions, illustrating the inlet and outlet fiuid passages.

Fig. 9 is an elevation of the sectional vane, and

Figs. 10, ll, 12 and 13 are detail sectional views of portions of the sectional vane.

In the embodiment of my invention as illustrated I employ standards or supports I, 2, fixed on a base plate 3. In the upper ends of the supports I, 2, there is secured, as by clamps 4, 5, a stationary shaft 6.

At diametrically opposite points and equidistant from the centre line of the stationary shaft 6, there are arranged the two rotary compressors or pumps, each of which is of identical construction. As seen more particularly in Fig. 6 each of said rotary compressors or pumps includes an external element or casing 1, constructed exter-' nally and centrally of its length with teeth in the form of a spur wheel 8. Centrally on the stationary shaft 6 there is fixed a spur wheel 9, with which the spur wheels 8 on both of the easings 1 mesh. The spur wheel 9 is shown constructed integral with two parts or rings III providing cylindrical surfaces. Around the surfaces of each of the rings I0 there is arranged a band II of rubber or other suitable resilient material.

The casings 1 are constructed exteriorly at both sides of the spur wheel 8 with cylindrical surfaces I2 which run on the resilient bands I-I.

Inside the casing 1 of each compressor or pump there is arranged an internal element or rotor l3, which is provided at the ends with trunnions l4, I5. The rotor I3, including the trunnions I4, IS, in the construction illustrated, comprises two longitudinal parts I6, I1, a centre part |8, positioned between the parts I6, I1, and closing the inner end of a longitudinal slot I9, and the end parts 28, 2|, positioned between the parts I6, I1, beyond the ends of the part I8. The several parts I6, I1, I8, 28 and 2| may be riveted or otherwise suitably connected together to form a one-piece structure. The cylindrical surface of the rotor I3, between the trunnions I4, I5, is provided with a rubber or other resilient cover 22, shown secured along the edges of the slot I9 by screws 23.

The rotors |3 are eccentrically arranged "within and in rolling contact with the walls of their respective casings 1, so that crescent-shaped spaces or chambers 24 are formed between the rotors I3 and their casings 1. The trunnions I4, I5, serve for rotatably maintaining the rotors I3 in contact with the walls of the casings 1, and they are journalled in ball bearings 25see more particularly Fig. 3--arranged in blocks 26, which are constructed at the sides with lugs 28. The blocks 26 for the two bearings 25 at the same end of the rotor I3 are connected by means of bars 21, the 20 ends of which are reduced and screw-threaded and engage in holes in the lugs 28 at the sides of the blocks 26, and are adjustably secured therein by nuts 29. The bars 21, through the medium of the blocks 26 and bearings 25 serve for applying the requisite adjustable pressure on to the rotors I3 inside their respective casings 1.

Around the stationary shaft 6, centrally between the bars 21 is arranged a ball bearing.30. At the inner side of each of the bars 21 is arranged a guide piece 3| of U shape in cross-section. The guides 3| are slidably connected to the bars 21 by means of pins 32 which are slidable in holes in the bars 21. Set-screws 33 screwed through the bars 21 into engagement with the backs of the guides 3| serve for operating the guides 3| or forcing them into and maintaining them in contact with the outer race ring of the ball bearing 38. These set-screws 33 enable the axes of the trunnions I4, I5, to be positioned and maintained in a plane which passes through the centre of the stationary shaft 6.

The bars 21 at one side of the arrangement are each constructed at the outside centrally of their length with projections 34, in which are formed holes 35 with which the driving means engage. The driving means includes a pulley 36 rotatably arranged on the stationary shaft 6, and constructed with a flange 31, which carries pins 38 which engage in the holes 35 in the projections 34. 39 are retaining collars for the pulley 36.

In the longitudinal slot I9, in each of the rotors I3 is arranged a vane 48, which slidably engages in the slot I9 and is maintained in contact with the wall of the casing 1 and serves for dividing the crescent-shaped space 24 into suction and compression chambers. The vane 40 is shown comprising four leaves or blades 0, b, c, d, which are placed side by side inside the slot l9, and are independently slidable in relation to each other to ensure separate lines of contact between each of the leaves and the wall of the casing 1 to prevent leakage between the vane 40 and wall from the compression to the suction chamber. In the bottom of the slot I9 between the part I8 and the inner ends of the leaves of the vane 40, helical springs 4| are positioned, which function to force the outer edges of the leaves into contact with the wall of the casing 1. Between the inner ends of the springs 4| and the part |8 there is positioned a plate 42 which carries a centering pin or projection 43 for each spring 4|. The inner ends of the leaves of the vanes 40 are constructed with slots 44 into which the outer ends of the springs 4| project. Each leaf is constructed with two foot pieces'45, which project into the slots 44 of the other leaves and are engaged by the two springs which operate said leaf. As shown in connection with Figs. 9 to 13 of the drawings, the foot pieces 45 of the one outside leaf a project into the slots a a ,-see Fig. 9; the foot pieces 45 of the other outside leaf 1), into slots b b the foot pieces 45 of the one inner leaf 0, into slots 0 c and those of the other inner leaf d into slots (1 The springs 4| of the respective leaves engage their respective foot pieces 45 and are able to move the leaves independently in the slot l8 so as to keep all the leaves of the vane 40 independently in contact with the wall of the casing 1. This construction enables wide or heavy springs to be used for each leaf, as the width of the springs employed is not limited by the thick- I ness of the leaves as it would otherwise be.

In each end of the casing 1 there is arranged an end member or disc 46 which is stationary relative to the casing 1 and around which the casing 1 is adapted to rotate. Said end member or discs 46 fits the casing 1, is in contact with the end of the rotor l3 and vane 40, and closes the end of the crescent-shaped space 24. The end members or discs are shown fitted with piston rings 41 to prevent leakage from the space 24. The disc 46 is constructed with an eccentric hole 48 through which the rotor trunnion pro jects. Around the trunnion is provided a stuffing box and gland 49 to make a fluid-tight joint. To each of the end members of discs 46 there is secured by screws 50 a plate or bar 5|, near the ends of which are formed square projections or pins 52. The bars 5| at the same end of both pumps are connected together by means of parallel bars 53 in which are provided slots in which engage the square projections 52; 54 being setscrews for adjusting purposes to ensure the end members 46 being non-rotatably maintained in position in the ends of the casings '1, so that the axes of the casings 1 and rotors l3 and central stationary shaft 6 lie in a common plane. The parallel bars 53 at both ends of the compressors or pumps are connected at both sides of the central stationary shaft '6 by means of turnbuckles or bars 55 having oppositely handed screwthreaded projections 56 which have screw-threaded engagement with holes in the bars 53. These turnbuckles 55 will enable the end members or discs 46 to be forced into position in the ends of the casings 1 into contact with the ends of the rotors I3 and their vanes 40, to make fluidtight joints.

Means are illustrated in Fig. 1 for ensuring that there shall be positive rotation of the rotors l3 inside their respective casings 1. This means is shown comprising a toothed wheel 51 fixed on the stationary shaft 6, and toothed wheels 58 on each of the rotor trunnions l4 meshing therewith and adapted to roll around the same.

The inlet for the fluid which is to be compressed or pumped in each compressor or pump is provided in the end of the rotor trunnion l4. The inlet passage 59 extends longitudinally of the centre part 20 of the trunnion to a point where it communicates with a radial or lateral passage 66. In the one side of the slot I9 opposite the passage 60 there is' fitted an L-shaped plate 6|, and behind the one and longitudinal arm of said plate 6| and in the wall of the slot I9 is formed a horizontal groove 62, which communicates at one end through a hole in the plate 6| with the lateral passage 60, and at the other end with a right-angled groove 63, formed in the wall of the slot 9 behind the other and transverse arm of the plate 6| and opening into the crescentshaped space 24 at the back or suction side of the vane 40-see Fig. 7. The outlet for the compressed fluid is similarly provided inthe other .side of the slot, 9 in the rotor, l3. It is formed through the right-angled passage 64 leading into the horizontal passage 65, which passages are covered by the L-shaped plate 66, and which communicate through a hole in the plate 66 and a lateral passage 61 with a horizontal outlet passage 68 through the central part 2| of the other trunnion l5.

As shown more particularly in Fig. 5, a tubular casing 69 is screwed on to the end of each trunnion H5, in which casing is fitted a pair of cupleathers 16 secured by nuts 1| on a screw-threaded hollow centre piece 12. These cup-leathers 10 are arranged so that the pressure of the compressed fiuid tends to make a fluid-tight joint with the casings and around the hollow centre piece 12, whichlatter is not attached to thetrunnion I5. The end of the casing 69 is closed by a cap 13. The inner end of the centre piece 12 is in communication with the outlet passage 68 through the trunnion l5. 0n the outer end of the screw-threaded centre piece 12 in each casing 69 there is screwed a connection 14, which is fashioned with a solid projection 15 which engages in the bifurcated extremity of an arm 16 fixed to the top of the block 26 carrying the bearing 25 around the trunnion l5. Near the end of the stationary shaft 6 there is attached a swivel piece or connection, comprising a sleeve 11 which fits around the shaft 6 and is kept in position thereon by nuts 18; packing in the form of piston rings 19 being arranged between the sleeve .11 and shaft 6. 80 are tubes placing the connections 14 in communication with a circular groove 8| formed around the centre shaft 6 at the centre of the sleeve 11. From the annular groove 8| transverse holes 82 communicate with a longitudinal axial hole 83 extending to and through the outlet end of the shaft 6. From the end of the outlet 83 the fluid can be discharged as required.

In the operation of this embodiment of my invention, as shown, rolling rotary motion is imparted to the rotors |3 inside the casings 1, through the pulley 36 and pins 38 and the arrangements comprising the bars 21, blocks 26 and bearings 25. The frictional rolling contact between the surfaces of the rotors l3 and the walls of the casings 1 rotates the latter around their own axes and rolls them around the rings ill.

The engagement of the spur wheels 8 with the stationary central toothed wheel 9 ensures positive rolling rotation of the casings 1, while the engagement of the toothed wheels 58 on the rotor trunnions M with thestationary toothed wheel 51 on the shaft 6 ensures positive rolling rotation of the rotors l3 inside their respective casings. the vanes 40 to rotate in contact with the walls of the casings 1, and through the inlet passages 59, 60, 62, 63, in communication with the crescent-shaped spaces 24 at the back or suction side of the vanes 46, to draw in the fluid, while the compressed fluid is expelled from the crescentshaped space 24 at the front or compression side of the vanes 46 through the outlet passages 64, 65, 61, 68, 12, 14, 80 8|, 82 and 83, discharging at the outlet end of the shaft 6. I

What I claim as my invention and desire to protectby Letters Patent is:

This movement of the rotors i3 causes 1. A rotary compressor or pump having inlet and outlet passages and including a plurality of rolling rotatable casings arranged to roll around a common centre, a cylinder fixed around said centre around and in contact with which the easings roll, a rotor in each casing which is eccentrically arranged therein and rolls in frictional contact with the internal wall thereof, the axes of said casings and rotors being fixed in relation to each other, a sliding vane carried by each rotor which slidably engages with the wall of the casing and divides the crescent-shaped space between the rotor and casing, and means for rolling the casings around the common centre, as set forth.

2. A rotary compressor or pump having inlet and outlet passages and including a plurality of rolling rotatable casings arranged to roll around a common centre, a cylinder fixed around said centre around and-in contact with which the casings roll, a rotor in each casing which is eccentrically arranged therein and rolls in frictional contact with the internal wall thereof, the axes of said casing and rotor being fixed in relation to each other, a sliding vane carried by each rotor which slidably engages with the wall of the casing and divides the crescent-shaped space between the rotor and casing, means for rolling the casings around the common centre, a toothed wheel on each casing, and a further fixed toothed wheel arranged around the common centre with which the wheels on the casings mesh to ensure positive rotation of the casings, as set forth.

3. A rotary compressor or pump having inlet and outlet passages and including a plurality of rolling rotatable casings arranged to roll around a common centre, a cylinder fixed around said centre around and in contact with which the easings roll, a rotor in each casing which is eccentrically arranged therein and rolls in frictional contact with the internal wall thereof, the axes of said casing and rotor being fixed in relation to each other, a sliding vane carried by each rotor which slidably engages with the wall of the casing and divides the crescent-shaped space between the rotor and easing, trunnions on the rotors, bearings for the trunnions, and means which {adjust-ably connect the trunnion bearings to enable pressure to be adjustably applied to the rotors through the trunnions, and means for rolling the casings around the common centre, as set forth. I

4. A rotary compressor or pump having inlet and outlet passages and including a plurality of rolling rotatable casings arranged to roll around a common centre, a central stationary shaft having a cylindrical surface around and in contact with which the casings roll, a rotor in each casing which is eccentrically arranged therein and rolls in frictional contact with the internal wall thereof, the axes of said casing and rotor being fixed in relation to each other, a sliding vane carried by each rotor which slidably engages with the wall of the casing and divides the crescentshaped space between the rotor and casing, trunnions on the rotors, bearings for the trunnions, means which adjustably connect the trunnion bearings to enable pressure to be adjustably applied to the rotors through the trunnions, and driving means combined with the means for applying pressure to the rotors which roll the easings around the cylindrical surface provided around the central stationary shaft, as set forth.

5. A rotary compressor or pump having inlet and outlet passages and including a plurality of rolling rotatable casings arranged to roll around a common centre, a cylinder fixed around said centre around and in contact with which the casings roll, a rotor in each casing which is eccentrically arranged therein and rolls in frictional contact with the internal wall thereof, the axes of said casing and rotor being fixed in relation to each other, a sliding vane carried by each rotor which slidably engages with the wall of the casing and divides the crescent-shaped space between the casing and rotor, relatively non-rotatable end members fitted in the ends of the casings next the ends of the rotor and vane and closing the crescent-shaped space, means connecting the corresponding end members of diametrically opposed casings to maintain the end members in correct position in the ends of the casings, and means for rolling the casings around the common centre, as set forth.

6. A rotary compressor or pump having inlet and outlet passages and including a plurality of rolling rotatable casings arranged to roll around a common centre, a cylinder fixed around said centre around and in contact with which the casings roll, a rotor in each casing which is eccentrically arranged therein and rolls in frictional contact with the internal wall thereof, the axes of said casing and rotor being fixed in relation to each other, a sliding vane carried by each rotor which slidably engages with the wall of the casing and divides the crescent-shaped space between the casing and rotor, relatively non-rotatable end members fitted in the ends of the casings next the ends of the rotor and vane and closing the crescent-shaped space, means connecting the corresponding end members of diametrically opposed casings to maintain the end members in correct position in the ends of the casing, adjustable means for moving the end members longitudinally of the casing relative to the rotor, and means for rolling the casings around their common centre, as set forth.

7. A rotary compressor or pump having inlet and outlet passages and including a plurality of rolling rotatable casings arranged to roll around a common centre, a cylinder fixed around said centre around and in contact with which the casings roll, a covering of resilient material around said cylinder, a rotor in each casing which is eccentrically arranged therein and rolls in frictional contact with the internal wall thereof, a sliding vane carried by each rotor, which slidably engages with the wall of the casing and divides the crescent-shaped space between the rotor and casing, and means for rolling the casings around the common centre, as set forth.

8. A rotary compressor or pump, including a stationary central shaft, a plurality of casings arranged around and equidistant from said central shaft, a cylinder fixed on the stationary shaft around which the casings roll, a rotor eccentrically arranged in each casing, a sliding vane carried by said rotor and in frictional contact with the wall of the casing, relatively non-rotatable end members closing the ends of the casings 'at each end of the rotor, trunnions on the ends of the rotors which work in eccentric holes in the end members, bearings for the trunnions, means connecting the bearings of the trunnions of each rotor at each side of the casings, means for applying pressure to the rotors through the means connecting their bearings, adjustable means for maintaining the end members in nonrotatablerelation to the casings and rotors, adjustable means for maintaining the end members in operative position relative to the rotors and vanes, in the ends of the casings, driving means for rolling the rotors in the casings and rolling the casings around the central cylinder, the trunnions at one end of the rotors being constructed with passages to lead the fluid into the casing behind the vane, and the trunnions at the other end of the rotors being constructed with passages to lead the compressed fluid from the casings at the front of the vane to the outlet, as set forth.

9. A rotary compressor or pump having inlet and outlet passages and including a plurality of rolling rotatable casings arranged to roll around a common centre, a cylinder fixed around said centre around and in contact with which the casings roll, a rotor in each casing which is eccentrically arranged therein and rolls in frictional contact with the internal wall thereof, the axes of said casings and rotors being fixed in relation to each other, a sliding vane carried by each rotor which slidably engages with the wall of the casing and divides the crescentshaped space between the rotor and easing, means for rolling the casings around the common centre, and means for applying pressure to each internal rotor in a direction at right angles to the line of contact with the wall of its casing, as set forth.

10. A rotary compressor or pump having inlet and outlet passages and including a plurality of rolling, rotatable casings arranged to roll around a common centre, a cylinder fixed around said centre around and in contact with which the casings roll, a rotor in each casing which is eccentrically arranged therein and rolls in frictional contact with the internal wall thereof,

the axes of said casings and rotors being fixed in relation to each other, a vane, comprising a. plurality of leaves, carried by the rotor, which leaves slidably engage with the wall of the casing and divide the crescent-shaped space between said casing and rotor, slots in the leaves, and foot pieces on the leaves engaging in said slots, and springs for each leaf working in said slots and engaging the foot pieces for maintaining the leaves independently in contact with the wall of the casing, and means for rolling the casings around the common centre, as set forth.

11. A rotary compressor or pump having inlet and outlet passages and including a plurality of rolling rotatable casings arranged to roll around a common centre, a cylinder fixed around said centre around and in contact with which the casings roll, a rotor in each casing which is ec centrically arranged therein and rolls in frictional contact with the internal wall thereof,

the axes of said casings and rotors being fixed in relation to each other, a sliding vane carried by each rotor which slidably engages with the wall of the casing and divides the'crescentshaped space'between the rotor and casing, end members which are relatively non-rotatable in the casings and are fitted in the ends of each casing next the ends of the rotor and vane and close the crescent-shaped space between the casing and rotor, and means for rolling the casings around the common centre, as set forth.

12. A rotary compressor or pump havinginlet and outlet passages and including a plurality of rolling rotatable casings arranged to roll around a common centre, a cylinder fixed around said centre around and in contact with which the casings roll, a rotor in each casing which is eccentrically arranged thereinvandrolls in frictional contact with the internal wall thereof, the axes of said casings and rotors being fixed in relation to each other, trunnions on the rotors, a sliding vane carried by each rotor which slidably engages with the wallof the casing and divides the crescent-shaped space between said casing and rotor, end members relatively nonrotatable to the casings and fitted in the ends of each casing next the ends of the rotor and vane and closing the crescent-shapedspace between the casing and rotor, said end members having eccentric holes through which the trunnions pass, stuffing boxes and glands in said eccentric holes, and means for rolling the casings around the common centre, as set forth.

13. A rotary compressor or pump having inlet and outlet passages and including a plurality of rolling rotatable casings arranged to roll around a common centre, a cylinder fixed around said.v

centre around and in contact with which the casings roll, a rotor in each casing which is eccentrically arranged therein and rolls in frictional contact with the internal wall thereof,

the axes of said casings and rotors being fixed v in relation to each other, a sliding vane carried by each rotor which slidably engages with the wall of the casing and divides the crescent shaped space between the rotor and casing, end

ing and rotor, adjustable means for moving the end members longitudinally of the casing relative to the rotor, and means for rolling the casings around the common centre, as set forth.

BERNARD LIGH'I'MAN. 

